Micromate® External Trigger Cable
The World’s Most Trusted Monitor — Vibration · Noise · Air Overpressure
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Instruction Sheet
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Purpose
This bulletin describes the procedure for connecting an External Trigger Cable (Part No. 721A1401)
to the Micromate and using this external trigger cable to trigger and record waveform events on
one or more Micromate units. The External Trigger cable will only work while the Micromate is
monitoring in waveform mode.
Explanation
When the optional auxiliary I/O has been configured for an External Trigger, the Micromate will
monitor the input signal from the External Trigger Cable for a voltage level change. The external
trigger can be used to trigger the Micromate at a specific time or it could be used to synchronize
the triggering of up to six Micromate units. The Micromate will determine the level, high or low,
of the input before entering monitor mode and automatically start recording within one sampling
period when the signal level changes from:
1. A high to a low level – This is referred to as a Wire Make. The two wires start out not connected
and are then connected by a push button or vibration event.
2. A low to a high – This is referred to as a Wire Break. The two wires started out connected and
this connection is broken by a push button or vibration event.
If the external trigger does not change its state (trigger mechanism fails), the individual Micromates
will still trigger based on their respective vibration and overpressure configuration setups.
As an additional feature, with multiple Micromates using the wire make configuration, if the trigger
mechanism fails, the first Micromate to trigger from the vibration or air overpressure will drive the
external trigger signal low within two samples of this trigger. This will force the remaining units
to start recording data. This feature is not available with the external trigger configured as a wire
break.
Example Applications
1. When an operator sees that a train has reached a specific point, the operator could activate the
external trigger by pressing a button or toggling a switch. This would cause the Micromate to
trigger and start recording data.
2. Install four Micromates in a building, each on a different floor, and connect the external triggers
of each Micromate to a contact that will be opened or closed by the vibration event. The
activation of the contact will cause all of the Micromates to trigger and start recording data.
The results from each unit can help determine the propagation of the vibration through the
building.
3. Install up to six Micromate units and connect all of the external triggers in parallel as a wire
make. Set the trigger levels on each of the Micromates such they will be triggered by an
external event. As soon as one of the Micromates is triggered it will drive the external trigger
signal low and force all of the remaining five units to start recording data.
